This invention pertains to an operator for a casement-type window which always acts near a free outer edge of the window sash for improved action in opening and closing the window throughout the operating life of the operator.
A window of the general type to which the invention disclosed herein relates is shown in Gill U.S. Pat. No. 2,948,027. In such a window, the sash is mounted adjacent one edge at the top and bottom on slider structure whereby said edge of the sash has both combined linear and pivotal movements, along with pivotal movement of the sash. A constraining link is connected between the sash and the window frame for guiding the sash movement.
Many different structures are known for a casement-type window operator wherein a manually operated pivotal operating arm is either directly or indirectly connected to the window sash for causing opening and closing movement thereof.
One example of an operator for the casement-type window is shown in Reynaud U.S. Pat. No. 3,085,299 wherein a pivotal operating arm carries a member at an end thereof which moves along a track associated with the window sash during opening and closing movement of the window and with the movement of the member being in a curved path about the pivot axis of the operating arm. With such structure, the point of application of opening and closing force to the window sash changes, dependent upon the degree of window opening, and the mechanical advantage available to open the window is reduced with increased opening of the window.